Checks that variable assignment does not occur in conditional statement of ternary.

Usually, the standard descriptions are quite explicit/directive. Similar to the error messages. So maybe instead of saying what the sniffs checks, I would suggest describing what the sniff expects. Something like:

"There should be no assignments in the condition part of ternary."

This might need some more polishing but should give the general idea. Checking other descriptions might help as well.

If incorrect will throw: "Variable assignment found within a condition. Did you mean to do a comparison?"

I believe that the sniff documentation usually does not include the error message displayed, so I suggest not including it here unless there is a reason to include it for this particular sniff.

Tried to clarify standard description and improve readability

Thanks for improving the description. I just realized that I misled you with the text I suggested. This sniff throws a warning and not an error, so we should not use should. Instead, we could say something like it is recommended or some other variation. Could you please update the description to account for that?

This sentence seems a bit confusing to me because of the use of the word "assigned". The sniff is not about assigning the result of a ternary comparison to a variable. The sniff is triggered whether or not the result of the ternary is assigned to a variable. At the same time, the sniff is precisely checking if there is no assignment in the condition part of the ternary.

Maybe this could be rephrased to avoid this confusion? I also wonder if it would be better to include just the ternary without the echo and the assignment to variable in the examples.

tried to clarify

I believe it is more common to use "condition" instead of "conditional statement" to refer to the first expression of a ternary, but I could be wrong. Reference: https://en.wikipedia.org/wiki/Ternary_conditional_operator. I found no mention of "condition" or "conditional statement" in the php.net page about ternaries: https://www.php.net/manual/en/language.operators.comparison.php. We might need to update the text for the valid and invalid examples as well.

Also, the sentence reads better to me if the article "a" is added before "ternary". That being said, I'm not a native speaker, so let me know if that is not the case.

Similar to the above, the sentence reads better to me if we add the article "the", but feel free to ignore this comment if that is not the case.

Just a nitpick, but usually, the code examples are not indented and should have no spaces. So, the initial version was correct. It doesn't have a noticeable impact in this case, and this is just a single line, but for multiple line code samples, it makes a difference.

This is another nitpick, but I suggest using a strict comparison instead of a loose comparison in the valid example so that it follows coding best practices.